1. Field of the Invention
The present invention relates to soil improvement technology used in various applications such as road construction, land development and the reinforcement of embankment slopes, and in particular relates to a soil improving agent including a soil hardening agent and a ground improving agent, a soil improving method including a soil hardening method and a ground improving method, and an improved ground which makes it possible to solve the problems associated with secondary damage such as soil contamination and groundwater contamination due to various earthworks, and which makes it possible to harden the surface of easily scattered soil in order to prevent wind damage.
2. Description of the Prior Art
In the prior art, because soil strength is increased by means of an aggressive improvement method using soil improvement materials such as cement-type hardening agents which include heavy metals, large quantities of lime and large quantities of normal cement, this creates problems including secondary damage such as soil contamination and groundwater contamination.
Namely, the use of such prior art soil improving materials has the following disadvantages:
1. When a cement-type hardening agent which includes heavy metals is used, the soil becomes contaminated by the heavy metals. Further, these heavy metals can also contaminate the groundwater.
2. When large quantities of lime and normal cement are used, operations can be hazardous due to the large quantity of heat generated. Further, after hardening has taken place, an unstable structure is created due the occurrence of cracks and the like. Moreover, because a complete mixing of cement and the like is difficult to achieve, the resulting structure lacks uniformity. Furthermore, in the case where lime and ordinary cement are used, the soil itself is killed, and after hardening of the cement and the like, the water permeability deteriorates and a weak stratum is created in the boundary where such soil improvement materials are used. Consequently, these prior art soil improving materials are considered to be inadequate.
3. When lime and ordinary cement are used, these materials require the mixing of large amounts of powdered materials, and this creates dust problems.
4. When lime and ordinary cement are used, because no improvement of the organic soil characteristics are achieved for the soil particles themselves, there is a rough improvement in density, but because there are few gaps between the soil particles, the improved ground has poor water permeability, and as a result, the soil structure lacks uniform strength.